ABSTRACT Extracorporeal membrane oxygenation (ECMO) use continues to increase as a supportive measure for cardio-respiratory failure. Pediatric patients with severe, acute left ventricular (LV) systolic dysfunction are often supported with venoarterial (VA) ECMO as a short-term bridge to recovery, transplant or a ventricular assist device (VAD). ECMO provides temporary gas exchange and increased cardiac output to end organs. Lack of egress of blood from the LV can lead to over-distension and elevated LV end diastolic pressure (LVEDP), which reduces myocardial oxygen delivery and recovery. The risk of progressive increase in left- sided filling pressures needs to be monitored closely to avoid the deleterious effects of left-heart distention. Left ventricular distention in patients with profoundly reduced left ventricular contractility is a major risk factor for poor myocardial recovery and failure to wean from ECMO. Mechanical decompression of the left-heart during ECMO is sometimes required, as a life-saving intervention. For patients who do not have open access to the heart for surgical decompression (i.e. post-operative cardiac patients), left ventricular decompression is most commonly accomplished by percutaneous transseptal puncture followed by either septostomy, placement of a drain device to keep the atrial communication patent, and placement of a pVAD such as Impella 2.5 which is only available for adults, is hemolytic, and is extremely expensive. Due to the lack of an FDA-approved device for this indication, options for decompression represent off-label use, and none of these devices is designed for pediatrics. The goal of this project is to design, test, and produce a line of pediatric and adult left heart decompression catheters suitable to be used in patients on VA ECMO for acute, severe LV systolic dysfunction. The MC3 InterSept? catheter line will include lengths and diameters to cover the entire spectrum of sizes required for the pediatric population from 2 kg to fully-grown patients, for both low flow left heart decompression and high flow total ventricular assist. Phase I captured detailed design inputs for the population by analyzing pediatric CT scan data from clinical cases at The University of Michigan. User requirements were translated into design inputs/outputs by MC3's team of experienced cannula design engineers. Feasibility was established by evaluating performance of the InterSept against specific criteria unique to use in the pediatric application. With Phase II funding, the full range of InterSept will be optimized, verification/validation testing will be completed, the design will be transferred to in-house MC3 manufacturing, and FDA and CE mark submissions will be filed using the ECMO pathway in the US and the Class 3 CE Mark pathway in accordance with the new European Medical Device Regulation. We have assembled a synergistic team of experts, clinicians, marketers, manufacturers and engineers who are uniquely qualified to carry out the proposed work.